On the planet, how much of global warming is a natural trend and how much of it is man made? I've asked this question to a number of climate change experts and nobody can provide a good answer to this simple question. Some think it is 90/10, some 70/30 and some 50/50.

Last edited by mmasters on Sat 02 Dec 2017, 22:42:45, edited 1 time in total.

mmasters wrote:On the planet, how much of global warming is a natural trend and how much of it is man made? I've asked this question to a number of climate change experts and nobody can provide a good answer to this simple question.

Simple, just figure out how much warming is a result of one half of your equation and subtract that from the total.

Of course in the real world the degree of complexity is very much higher than that because human effects have both warming and cooling effects and for a long time these were more or less in balance meaning our net impact was minimal. Then that so-and-so President Nixon got Congress to pass the Clean Air Act and signed it in the early 1970's and by the time Governor Bill Clinton became President Clinton in 1993 the dimming from America and Europe was substantially reduced. China started taking up the dimming role in the late 1990's but by then the grace period had elapsed and warming had started to become discernible to the average person living in the higher latitudes.

I should be able to change a diaper, plan an invasion, butcher a hog, design a building, write, balance accounts, build a wall, comfort the dying, take orders, give orders, cooperate, act alone, solve equations, pitch manure, program a computer, cook, fight efficiently, die gallantly. Specialization is for insects.

mmasters wrote:On the planet, how much of global warming is a natural trend and how much of it is man made? I've asked this question to a number of climate change experts and nobody can provide a good answer to this simple question.

How much of the current atmospheric CO2 is due to anthropogenic emissions and how much is natural:30 billion tons per year from humans and 600 million tons from volcanic emissions (running average).

Water vapour does not spontaneously accumulate in the atmosphere leading to a pure H2O warming trend which would be natural. Water in the atmosphere is thermodynamically controlled and is not a dry gas like CO2. Thanks to precipitation any build up of H2O is self-limiting. We never had ocean boil off events in the geological record and such events would have occurred without this self-limitation. But we did have snowball earth events when ice albedo dominated solar insolation until volcanic CO2 build up allowed the ice hell trap to be broken.

The observed global temperature trend is solidly accounted for by the CO2 (and CH4, N2O, etc) accumulation, which induces an H2O build up due to the higher temperatures. The CO2-H2O tandem is the principle causal factor for the observed temperature trend. Not intrinsic variability of the system which is mostly the exchange of heat between in the oceans and the atmosphere:

mmasters wrote:On the planet, how much of global warming is a natural trend and how much of it is man made? I've asked this question to a number of climate change experts and nobody can provide a good answer to this simple question.

Natural global warming is caused by natural forcing mechanisms, while man made global warming is a product of human activity that results in the release of greenhouse gases and dark carbon and other things that affect the climate.

We can make a rough estimate of how much global warming is human caused by running global climate models on supercomputers. When these models are run, the amount of warming due to human generated greenhouse gases, for instance, is essentially identical to the amount of global warming that has occurred since the start of the industrial revolution. That suggests that essentially all the warming we see is human caused.

We know that in theory natural forcing mechanisms can also cause climate change, but we don't see any evidence that natural forcing mechanism (things like changes in solar activity, or increases in planetary dust loads) are changing right now. Since there is no natural forcing going on, then there should be no natural climate change going on. This also suggests that all the warming we see is human caused.

dohboi wrote:The upper ranges of estimates are more like something like 110% man made, since we should have been cooling a bit over the last hundred some years under natural cooling.

We have definitely broken the pattern of the last 3.3 million years. We are in an inter-glacial period and given the orbital dynamics we should be seeing a weak cooling trend instead of any warming trend. Thanks to the massive amount of carbon we are unleashing from both fossil and surface reservoirs, it appears that it will take several hundred thousand years for chemical weathering to remove the anthropogenic excess. That is, we are in the anthropocene.

mmasters wrote:On the planet, how much of global warming is a natural trend and how much of it is man made? I've asked this question to a number of climate change experts and nobody can provide a good answer to this simple question. Some think it is 90/10, some 70/30 and some 50/50.

It isn't a simple question. To get the answer to it, someone needs to have built a model that can backcast right through the change in temperature climbing out of the last glacial age. And account properly for the temperature changes from there into the Holocene, and then throughout the Holocene. Without that proven backcasting ability, you can't claim to know what the temperature should have been naturally, including coming out of the LIA.

It is far easier to do what ended up being done...just assume all warming is human caused.

Peak oil in 2020: And here is why: https://www.youtube.com/watch?v=2b3ttqYDwF0

"It is far easier to do what ended up being done...just assume all warming is human caused."

Not really. What is easier is to continue to wait for irrefutable proof that so many insist on having before they respond to the potential threat, which is largely what we've done. People will often react to educated guesses in proactive ways, but climate change/AGW has become so politicized, many people would continue denying it even if God came down, smacked them over the head and said; "YOU ARE FRYING THE ONLY PLANET YOUR CHILDREN WILL EVER HAVE. STOP!"

Blessed are the Meek, for they shall inherit nothing but their Souls. - Anonymous Ghung Person

As DS said, According to the Milankovitch cycles we should be starting to cool down. But there is no proof that M cycles are the cause of Ice Ages. M cycles have been going on longer than Ice Ages.

We owe our existance to the Sun. My instinct says the Ice Ages are caused by a Sun output cycle we don't understand. I don't know but I trust my instincts. Physics is also evolving...

That means what we do won't save us from Nature. But at the same time we could cook ourselves before the next Sun cycle kicks in, or the next M cycle gets going good. CO2 causes warming, does that beat out the Sun? I doubt it. But it's not nice to fool with Mother Nature

A Solar fuel spill is otherwise known as a sunny day!The energy density of a tank of FF's doesn't matter if it's empty.https://monitoringpublic.solaredge.com/solaredge-web/p/kiosk?guid=19844186-d749-40d6-b848-191e899b37db

baha wrote: CO2 causes warming, does that beat out the Sun? I doubt it.

We know CO2 in the atmosphere is changing now due to FF burning, and CO2 causes global warming. We can measure the amount of CO2 in the atmosphere very accurately, and then model the amount of warming increased CO2 should produce. That modeling matches what we see as the planet warms.

We also know the solar output isn't significantly changing. We can measure solar activity very precisely, and there are no changes other the sunspot cycle. There is some suggestion we are at a "low" in the sunspot cycle, but if anything that would produce cooling, not warming.

Trying to attribute current global warming to changes in the sun is magical thinking, since we know there aren't any changes occurring in the suns output that would cause warming..

I agree human caused CO2 is warming the planet. I am not attributing our current warming to the Sun. I am saying a Sun cycle that we have never observed is causing Ice Ages. When it starts happening we will observe it and think 'oh shit'.

Just a tiny change in the output of the Sun would cause an Ice Age. Just like a small change in the % of CO2 in the atmosphere will heat the planet...

A Solar fuel spill is otherwise known as a sunny day!The energy density of a tank of FF's doesn't matter if it's empty.https://monitoringpublic.solaredge.com/solaredge-web/p/kiosk?guid=19844186-d749-40d6-b848-191e899b37db

GHung wrote:"It is far easier to do what ended up being done...just assume all warming is human caused."

Not really. What is easier is to continue to wait for irrefutable proof that so many insist on having before they respond to the potential threat, which is largely what we've done.

There are many "potential" threats. Not the least of which is how humans treat each other, cosmic collisions, gamma bursts, continental sized basalt flows, super volcanoes, human based pollution effects (which is really what CO2 emissions are), all sorts of things. I am quite happy to react to one, you might like another, peak oilers yet another.

None of these require irrefutable proof to act, and as we can see from the peak oilers, irrefutable proof isn't even ENOUGH for a faith based person to change their mind.

GHung wrote: People will often react to educated guesses in proactive ways, but climate change/AGW has become so politicized, many people would continue denying it even if God came down, smacked them over the head and said; "YOU ARE FRYING THE ONLY PLANET YOUR CHILDREN WILL EVER HAVE. STOP!"

Climate change has become politicized, I agree. And that is probably the worst thing that could ever happen to it, in terms of being taken seriously by a large percentage of the population.

Peak oil in 2020: And here is why: https://www.youtube.com/watch?v=2b3ttqYDwF0

Well we know roughly the amount of CO2 we have spewed since the beginning of the Industrial age and we know roughly how much extra CO2 is in atmosphere since the baseline years of the advent of the Industrial age.From that scientists can estimate the extra heat forcing the additional CO2 has hadSo scientists say we are largely responsible for the extra warming and thus will be for the warming feedbacks it has triggered

onlooker wrote:Well we know roughly the amount of CO2 we have spewed since the beginning of the Industrial age and we know roughly how much extra CO2 is in atmosphere since the baseline years of the advent of the Industrial age.From that scientists can estimate the extra heat forcing the additional CO2 has hadSo scientists say we are largely responsible for the extra warming and thus will be for the warming feedbacks it has triggered

That one is easy. Simply invalidate the scientists. What good are people we don't understand anyway?

Blessed are the Meek, for they shall inherit nothing but their Souls. - Anonymous Ghung Person

Let's try a little bit of perspective. Especially when it comes to what might, or might not be done, with respect to global warming. We'll look at global diarrhea. I know...be patient.

Deaths among children under 5 yo: about 1.5 million/yr. About 15% of deaths in that age group. So we're not talking about all global PREVENTABLE deaths for all age groups. Or all children under 5 from all preventable causes. Just a very small group. A group with an easily treatable condition. Not an expensive treatment...literally pennies unlike AIDS, malaria and other insect delivered diseases, general malnutrition, etc. No debate over its existence as there is with climate change.

So different expectations but lets say the sh*t really hits the fan by 2050 and climate change just hurts the population with dislocations and economic upheavals but actually starts filling a lot of body bags. By then about 50 million children under 5 will have died from and cheap and easily preventable condition. And that 50 million body count represents just a very, very small % of the total global death count from PREVENTABLE diseases. And a treatment that causes no one to alter their lifestyle on little bit. Or decreases economic activity at all.

So the assumption seems to be that if the world is completely convinced of climate change it will make huge life altering changes in its activities. And yet with virtually no comparative cost to save the lives of 50 million children under 5 yo nothing will be done by this same group of folks.

Perhaps instead of spending so much time arguing over climate change based upon such an assumption being true perhaps folks should be a tad more focused on how they expect folks to react if the "truth" is accepted by the vast majority. No one on the planet can say they don't believe in the children death stats presented...we have the dead bodies as evidence piling up everyday.

ROCKMAN wrote: comparative cost to save the lives of 50 million children under 5 yo ....

This is the same argument made by Bjorn Lomborg in his 2001 book "The Skeptical Environmentalist" and in subsequent books like "Cool It". Lomborg accepts the reality of global warming, but argues that it would be more cost effective to spend precious money alleviating diarrhea in little children and other similar things, rather then spending big bucks to try to stop global warming.

The fatal flaw in the argument that you and Lomborg are making is that the problems with global warming get worse and worse through time as more and more CO2 accumulates in the atmosphere. By the time you go out 50-100 years from now we're going to be looking at sea level rise flooding parts of every coastal city in the world, and drowning low lying parts many of the most densely populated delta areas in the world, like the Nile Delta and the Ganges Delta and the Yellow River Delta.

When it comes to being cost effective, you can't spend too much when you're talking about drowning every coastal city and every delta on earth and turning hundreds of millions of people into climate refugees.

jedrider wrote:I thought mankind has essentially DOUBLED the amount of CO2 in the atmosphere. An equivalent change in the Sun's output would have us all cinder blocks already.

Not yet, so far we have increases the total CO2 content of the atmosphere by about 65% from baseline. At 2 ppmv per year increase rate we will need at least another 70 years to double the low pre-industrial estimate and 80 years from now to double the high pre-industrial estimate of CO2 already in the air.

I should be able to change a diaper, plan an invasion, butcher a hog, design a building, write, balance accounts, build a wall, comfort the dying, take orders, give orders, cooperate, act alone, solve equations, pitch manure, program a computer, cook, fight efficiently, die gallantly. Specialization is for insects.